[Enhancement] Add support for negatively acknowledging messages in Python functions

[lhotari]

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Motivation

Currently there's no way to explicly nack messages in Python functions.

Use case:
This would be useful in using a Python function as a dynamic router that forwards Pulsar messages to multiple other topics. In such a Pulsar function, it would be necessary to configure autoAck to false and handle acknowledgement only after the forwarded message has be successfully sent to the destination topic.
If this fails, the input message should be negatively acknowledged.

Solution

Add negative acknowledgement support to Pulsar Functions Python library and implementation.

Alternatives

No response

Anything else?

No response

Are you willing to submit a PR?

• I'm willing to submit a PR!